(RF110) A "must have" for anyone growing their own vines. Don`t guess when to pick. The Refractometer allows you to accurately measure the percentage of sugar in your grapes with just 2 or 3 drops of juice. Take a few strategic samples from throughout your vines and determine instantly the sugar content of your grape before picking. Very simple to use. Just press the juice sample down against the glass plate. Point it to a light source and look through the eyepiece to view the reading. Also, handy for taking quick readings during pressing. Exceptional quality. Accurately reads from 0% to 32% sugar (Brix) that easily converts to Specific Gravity. Comes with complete directions and portable carrying case. 6-1/2 inches long. Scale resolution: .20%, Accuracy: +/-2%.